The present invention is directed to brewing apparatus in general, and more particularly, to apparatus suitable for use in a microwave oven for brewing a brew substance into a liquid and a method of making such apparatus.
Disposable microwavable coffee brewers suitable for a one-cup serving have been described in the literature. In these brewers, water is added to a water reservoir and the brewer with water is placed over the consumer's cup or mug which is of any known type for receiving a hot beverage. The brewer and cup are then placed in a microwave oven wherein microwave brewing at appropriate settings may take approximately 5 or less minutes. During the brewing operation, the water is heated in the reservoir and at the desired temperature, the water is mixed with a charge of coffee in a brew chamber below the reservoir. The brewed coffee is eventually dispensed by gravity from the brew chamber into the drinking container.
One such microwavable coffee brewer is disclosed in U.S. Pat. No. 5,243,164, entitled “Beverage Maker” which was granted Sep. 7, 1993 to Erickson et al. In the Erickson brewer, a liquid reservoir includes at least one aperture at the bottom thereof for dispensing a brewed liquid into a drinking container. Filter paper is disposed over the at least one aperture at the bottom of the reservoir and a charge of coffee grinds is disposed over the filter paper. A partition of heat responsive film is disposed over the charge of coffee grinds and attached to the inside circumference of the reservoir to prevent liquid within the reservoir from mixing with the coffee grinds until the liquid reaches the proper temperature.
To brew coffee with the Erickson brewer, the reservoir is filled with a proper amount of water and disposed over a drinking cup or mug. Then, the reservoir and cup are placed into a microwave oven which is set to start with the desired settings for heating. As the temperature of the water reaches the melting temperature of the partition material, the partition ruptures and exposes the water to the coffee grinds for brewing. The brewed coffee releases by gravity to the cup through the filter paper and at least one aperture of the reservoir.
While the Erickson brewer mentions the use of a nitrogen purged (i.e. filled) retail bag for keeping multiple assembles preserved, the individual brewers, particularly their respective coffee charges, are not individually sealed. Accordingly, the freshness of the coffee will begin to degrade as soon as the multiple unit package is ruptured. Also, the Erickson brewer permits flow-through brewing immediately upon rupture of the partition, thereby prohibiting a gradual wetting of the grounds prior to the introduction of the brewing liquid into the serving cup. This absence of gradual wetting may allow air pockets to remain in both the grounds and the paper which, in turn, has the potential of compromising the extraction process in and around these air pockets.
Still further, the Erickson brewer provides no provisions for a filter paper layer above the grounds. One drawback of this design is that buoyant grounds may rise into the liquid reservoir, in turn, mitigating the hydraulic drag of the grounds remaining in the brew chamber and permitting a higher flow rate which eventually results in less extraction. Another drawback of this design is that the grounds should be retained and held where the fluid head pressure is the greatest (i.e. as low as possible relative to the centroid of the reservoir). Buoyant grounds floating on or near the surface of the liquid do not have the benefit of head pressure to aid in the extraction process. Moreover, the appearance of grounds in the liquid reservoir is aesthetically undesirable, and, if the reservoir is to be reused, a cleaning burden.
Accordingly, the present invention overcomes the foregoing described drawbacks of the current brewers by providing improved brewing apparatus and a method making the same.